Cerebral and peripheral tissue oxygenation in stable neonates: Absent influence of cardiac function

Abstract

Aim Cardiac function is a major factor for tissue perfusion and therefore may affect the tissue oxygen saturation. Aim was to analyse possible associations between cardiac function parameters and cerebral and peripheral tissue oxygenation in neonates on the first day after birth. Methods For the present study, we analysed secondary outcome parameters of a previously performed prospective single centre observational study. The prospective study was conducted at the Medical University of Graz, Austria between September 2011 and June 2013. We included preterm and term neonates who were admitted to the neonatal intensive care unit and in whom simultaneous near‐infrared spectroscopy measurements and echocardiography were obtained on the first day after birth. Cardiac function parameters were correlated to cerebral and peripheral tissue oxygen saturation and cerebral and peripheral fractional tissue oxygen extraction at the time of echocardiography. Results A total of 60 neonates of whom 47 were preterm and 13 were term (median gestational age: 34; IQR 33‐35 weeks, mean birth weight: 2276 ± 774 grams) were included. There were no statistically significant correlations between cardiac function parameters and regional tissue oxygenation parameters. Conclusion In the present study, we found no correlation between regional tissue oxygenation and parameters of cardiac function in cardio‐circulatory stable neonates on the first day after birth.

Peripheral muscle fractional tissue oxygen extraction in stable term and preterm neonates during the first 24 h after birth

“…In contrast to our present pFTOE within the first time period, Bruckner et al ( 18 ) published pFTOE values of median (IQR) 0.08 (0.04–0.15) in term and preterm neonates with a mean gestational age of 34 weeks within the first four to six hours after birth. These values were noticeably lower compared with pFTOE in our study [0.26 (95%CI 0.229–0.300)].…”

“…This observed discrepancy may be based on the fact, that peripheral regional oxygen saturation was clearly higher in the study by Bruckner et al [87% (80–92)] compared to the pTOI in our study (term neonates 71.5% [68.2–74.8]; preterm neonates 74.6% [73.1–76.0]). The differences in peripheral muscle oxygen saturation and consequently in pFTOE between Bruckner et al’s study ( 18 ) and our work may be explained by the different NIRS devices used (INVOS versus NIRO 200/NIRO 200NX), since the INVOS device shows higher tissue oxygen saturation compared to NIRO devices ( 19 , 20 ). Direct comparisons of these two devices have revealed a difference of up to ten percent, especially with increasing tissue oxygen saturation ( 20 ).…”

“…Possible relevance for pFTOE in clinical practice and therefore the need for reference values have been described in associations between pFTOE and cardiac function ( 18 ), partial exchange transfusion ( 21 ), ventilator modes ( 22 ), and carbon dioxide (CO 2 ) ( 23 ).…”

Effect of ventilator modes on neonatal cerebral and peripheral oxygenation using near‐infrared spectroscopy

“…Measures such as cardiac output or blood pressure reflect the macrocirculation and may not necessarily reflect perturbations in blood flow or oxygenation in the microcirculation, where oxygen exchange actually takes place. 4,[10][11][12] Other hemodynamic variables sometimes used, such as blood flow velocity obtained by Doppler is also often not reflective of the microcirculation. 13 Therefore, the impact of ventilation mode at the level of the microcirculation remains a question of interest in premature infants who are at greatest risk for damage due to alterations in blood flow and oxygen delivery.…”

“…A further issue complicates evaluation of ventilatory modes on cardiovascular function and oxygen delivery. Measures such as cardiac output or blood pressure reflect the macrocirculation and may not necessarily reflect perturbations in blood flow or oxygenation in the microcirculation, where oxygen exchange actually takes place 4,10‐12 . Other hemodynamic variables sometimes used, such as blood flow velocity obtained by Doppler is also often not reflective of the microcirculation 13 .…”